concealment writes: "Apple is making it more difficult for iPhone 4 owners to perform simple DIY repairs by replacing common Phillps head screws with a rare "pentalobe" screws. While newer iPhone 4s have included the screws from the factory, it is also Apple policy to replace any Phillips head screws with the new pentalobe screws whenever an iPhone 4 is taken in for service.

Wiens said that Apple had used a similar screw on early unibody MacBook Pros to secure the integrated battery, but later adopted a tri-wing screw for that purpose. The latest MacBook Airs, however, also use pentalobe screws on the outside case, making it difficult to perform what would otherwise be a simple swap of the SSD, for instance."

An electrical company decided that in order to prevent the users of their devices from opening them up, they designed a screw head that was not compatible with the common flat head type screws. This company was Philips.